This game is not that easy to be evaluated but I'll try anyway.
First of all it is very long and has a lot of content. If you don't skip the dialogues, it may take you 20 hours or so to read it all. At least it seemed so to me because at some moment I got tired and started using fast forward. You are better than me if you won't
Let's also admit that the graphics are good and don't feel generic. Visuals are certainly a strong point of Nephilim.
The game has a fantasy setting similar to RPG games. You have medieval world, magic, goblins and other monsters... However in a true RPG game you walk freely around the world, talk to characters, level up, collect loot, manage quests, conduct battles etc. Here, it's Renpy game so you just watch slideshows and occasionally make some choice. So it's just an inferior experience to a standard RPG in that aspect.
Okay, but you may say that this game is not about role playing, it's about sex. So let's talk about sex
Actually early in the game there is very little sex. The game begins in a very soft, romantic way, like it was written by a teenage girl for teenage girls. There is basically one girl, lot of kissing and looking deep in the eyes but not much more.
Around Chapter 3 the game drastically changes. I guess the Patreon backers started moaning for more erotic action so the author changed his style
Your chosen girl somehow loses her importance, a lot of new females appear and there are much, much more sexual scenes. The story takes some unexpected turns, like some pirates appearing. Unforunately I got tired at that moment and started skipping the dialogues so a lot of story details were lost to me.
Maybe if you won't get tired like me, you'll like it more.